About L-Aspartate
L-aspartic acid is a non-essential proteinogenic amino acid synthesized endogenously and abundant in dietary protein, so deficiency is essentially never seen. As a supplement it is most commonly used as a counter-ion in mineral chelates (potassium aspartate, magnesium aspartate, zinc aspartate). Standalone supplementation has been studied for fatigue and exercise performance in small, dated trials with conflicting results, and no modern meta-analysis supports a clinical effect. Important: L-aspartic acid is NOT the same as D-aspartic acid (DAA) — DAA is the stereoisomer with a small (and inconsistently replicated) testosterone literature. High intakes of free aspartic acid can theoretically contribute to excitatory neurotransmitter load, but no clear adverse-effect threshold is established. No RDA/UL.
What L-Aspartate supports
- Building block for proteins and intermediate in the urea/Krebs cycles
How much L-Aspartate to take
Clinical studies typically use 1000–3000 mg of L-Aspartate. No clinically established dose for free L-aspartic acid as a standalone supplement. Range reflects what older fatigue/ergogenic studies used; do not interpret as a therapeutic threshold. Note: D-aspartic acid (DAA) is a different stereoisomer with a separate (and weak) testosterone literature — not the same compound.
- Effective range
- 1000–3000 mg
Clinical evidence
Limited clinical evidence. No compelling RCTs for free L-aspartic acid supplementation in healthy adults; commonly used as a chelate counter-ion rather than for direct effect
NIH Fact Sheet